contrib: add editmerge script for editor conflict prompts

Adds a script that opens the editor to the conflict as part of the merge
process. This way you can fix the merge during the rebase instead of having to
pause the rebase, resolve --mark, rebase --continue.

Only works on unix.

contrib/editmerge

@@ -0,0 +1,58 b''
+#!/bin/bash
+# A simple script for opening merge conflicts in the editor.
+# Use the following Mercurial settings to enable it.
+#
+# [ui]
+# merge = editmerge
+#
+# [merge-tools]
+# editmerge.args=$output
+# editmerge.check=changed
+# editmerge.premerge=keep
+
+FILE=$1
+
+getlines() {
+  grep -n "<<<<<<" $FILE | cut -f1 -d:
+}
+
+# editor preference loosely based on http://mercurial.selenic.com/wiki/editor
+# hg showconfig is at the bottom though, since it's slow to run (0.15 seconds)
+ED=$HGEDITOR
+if [ "$ED" = "" ] ; then
+  ED=$VISUAL
+fi
+if [ "$ED" = "" ] ; then
+  ED=$EDITOR
+fi
+if [ "$ED" = "" ] ; then
+  ED=$(hg showconfig ui.editor)
+fi
+if [ "$ED" = "" ] ; then
+  echo "merge failed - unable to find editor"
+  exit 1
+fi
+
+if [ "$ED" = "emacs" ] || [ "$ED" = "nano" ] || [ "$ED" = "vim" ] ; then
+  FIRSTLINE=$(getlines | head -n 1)
+  PREVIOUSLINE=""
+
+  # open the editor to the first conflict until there are no more
+  # or the user stops editing the file
+  while [ ! "$FIRSTLINE" = "" ] && [ ! "$FIRSTLINE" = "$PREVIOUSLINE" ] ; do
+    $ED +$FIRSTLINE $FILE
+    PREVIOUSLINE=$FIRSTLINE
+    FIRSTLINE=$(getlines | head -n 1)
+  done
+else
+  $ED $FILE
+fi
+
+# get the line numbers of the remaining conflicts
+CONFLICTS=$(getlines | sed ':a;N;$!ba;s/\n/, /g')
+if [ ! "$CONFLICTS" = "" ] ; then
+  echo "merge failed - resolve the conflicts (line $CONFLICTS) then use 'hg resolve --mark'"
+  exit 1
+fi
+
+exit 0